The basic objective of the proposed research is the development of new reagents and strategies for the synthesis of complex organic molecules and polymers that are of biological interest. New reagents based on metal alkylidene complexes will developed for the synthesis of carbon-carbon double bonds. This chemistry will be designed to take advantage of the full potential of the olefin metathesis reaction in organic synthesis. These studies will involve the development of simple synthesis of tungsten alkylidene complexes to be used in the further studies. In the initial studies these alkylidene reagents will be used to convert esters and amines into vinylethers and enamines. The olefin metathesis reaction will be combined with the carbonylolefination reaction in intramolecular directed cyclizations of organic molecules that contain a carbonyl and an olefin. Olefin metathesis of dienes will result in direct cyclization. The techniques proposed can be used to prepare a family complex organic molecules of biological significance.